1. Field of the Invention
This invention relates to a computer system. More specifically, the field of the present invention is that of a computer system having bus and the ability to automatically configure circuit cards that are coupled to the bus.
2. Related Art
Computers and their associated bus architecture and protocol establish a framework upon which other items like integrated circuits and add-on circuit cards are based. The bus and bus controller provide a medium for the computer to communicate with the peripherals coupled to the bus. The Industry Standard Architecture (ISA) bus is an example of a bus architecture widely used in the computer industry as a standard bus expansion in most personal computers (PCs).
This bus architecture requires the allocation of system resources like memory, input/output (I/O) address spaces, Direct Memory Access (DMA) channels, and interrupt levels among multiple ISA cards. The ISA interface however, does not have any defined hardware or software mechanism for allocating these resources. As a result, configuration of ISA cards (circuit cards) is typically done with hardware jumpers. This procedure changes the decode maps for memory and I/O space and steers the DMA and interrupt signals to different pins on the bus. This procedure also requires that system configuration files are created and updated to reflect these configurations.
This prior art configuration procedure presents problems; because, the end-user must have a fair understanding of computer system configuration procedures to effect some of these configuration changes. The user typically must resolve any system resource conflicts that result from any configuration by referring to documentation provided by the system and card manufacturers. This procedure can sometimes be frustrating and unreliable.
Prior art bus standards, such as Micro Channel Architecture (MCA) and Extended Industry Standard Architecture (EISA), have both hardware and software implementations to identify system resources requested by a card. However, user intervention is still required for the resolution of conflicts that arise during any reconfiguration of the circuit cards. These implementations are also not compatible with the installed base of PCs with ISA card slots.
In order to relieve the burden of users reading manuals to configure circuit cards, many prior art system designers provide software to help in the configuration of these circuit cards. However, the responsibility of resolving resource conflicts that result after a manual reconfiguration of these circuit cards is still left to the user.
Prior art systems have been unable to provide any hardware and software mechanism that will automatically configure these ISA circuit cards when inserted into Personal Computer systems. Therefore, a method and apparatus is needed that will enable these cards to be configured into a bus architecture based computers system, without the need for any user intervention. The use of these circuit cards should be such that the user simply has to plug (insert) the cards in a computer system, without any manual configurations or resource conflict resolutions by the system user. The system should automatically resolve resource conflicts between add-on circuit cards. This automatic conflict resolution should optimally allocate system resources between the add-on cards and other devices in the system without any user intervention. Prior art systems have been unable to achieve this level of automatic configuration.